Dynamo-electric machine.



G. fSYRE.

DYNAMO ELECTRG MACHINE.

APPLICATION FILED MAY 16, 1912.

1,077,942, Paten-ned Nrn/.4,1913

UNTTED sTATEs PATENT OFFICE.

GORDON SAYRE, 0F DAYTON, OHIO, ASSIGNOR TO THE APPLE ELECTRIC COMPANY, OF DAYTON, OHIO, `.A CORPORATION OF OHIO.

DYNAMO-ELECTRIC MACHINE.

Specication of Letters Patent.

Patented Nov. 4, 1 913.

To all whom it may concern: l

Be it known that I, GORDON SAYRE, a citil zen of the United States, residing at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a specification.

My invention relates to limprovements in constant current regulating dynamo electric machines.

One of the objects of my invention is to provide aself regulating constant current electric machine, which will maintain prac tically constant its own current output under large variations of speed,

Another object of my invention is to provide a regulator of the character described, which is an inherent part of the machine structure, and which is entirely devoid of any automatically moving or complicated parts or windings.

Other and further objects of my invention will become readily apparent to persons skilled in the 'art from` a consideration of the following description, taken in conjunction with the drawings which are a part hereof wherein: l

Figure 1 is a schematic arrangement of the circuits, diagrammatically represented. Fig. 2 shows diagrammatically the normal distribution of electro-motive-force around the commutator,l with the brushes on the commutating points of a four pole dynamo electric machine, having a cross connected armature. Fig. 3 shows asimilar view, with the commutating points and the oints of maximum and minimum potential very much displaced relatively to each other, due to the reaction of the armature.

.In all of the views the same reference characters are used to indicate similar parts.

My re ulator is especially adapted for use in' lighting vehicles and for igniting and starting the engines .of vehicles, such as automobiles, motor boats and the like; for train lighting systems wherein the dynamo is driven from the axle and its s eed is directly determined by the speed o same. It

is also adapted for use with lstorage bat-v teries wherewith the battery may be oated on the line ywithout fear of reversal of the dynamo electric machine, as when series* wound field magnets are used-in connection therewith.

In the foregoing situations, where dynamo electric machines are used with variable speed vehicles, it is highly essential that the machine shall generate current of sufficient volume, at relatively slow speed, and

that any increase of-speed cannot operate to proportionately increase the strength of the current, for otherwise the current would increase proportionately to the increase of speed and the translating devices connected with the circuits, such as lamps, induction coils and other such current responsive devices or instrumentalities, would be overloaded, resulting in the burning out of such devices and the dangerous over-loading and heating of the field magnets and armature of such dynamo-electric machines.

My present system of regulation has been operating to my entire satisfaction on small installations that are required for lighting automobiles and for furnishing current for producing the spark for the internal combustion engine used to operate such vehicles, the electromotive forcev in such installations not having exceeded 12 to 15 volts and the current having been maintained at any point within the normal range of speed from 120() to 300() R. l?. M. at 8 to 10 amperes.

In Fig. 1, 5 and 6 represent the mains of an elect-ric working circuit for distribution of the current, generated by my dynamo elect-ric machine, provided with my constant current regulator. The main 5 is connected to the positive brush 7 and the main 6 is connected to the negative brush 8 as usual in quadrupolar dynamos, of which the diagram represents one of the type. The shunt field winding is composed of the coils 9, 9 and 10, 10 connected in series, the terminals being connected with their respective mains as at 11 and 12. This feature is substantially common in shunt wound dynamos. At a point between the coils 9 and 10 a wire 13 is connected to the intermediate regulating brush 14. The main brushes, 7, 8, and the auxiliary regulating brush 14 bear on the commutator 15.

The brush 14, is shown in dotted lines, as at 16, to indicate-the range of movement of the brush 14 as -a means determining the strength of the current that is to be automatically maintained in the mains 5 and 6. 1t is only necessary to move t-he brush 14, and fix it in selected position, when the current is to be increased, or decreased, as the case may be. llf it is desirable that 10 amperes be maintained in the main circuit,

between the mains o and 6, under varying changes of speed, then the brush should occupy approximately a position shown in full lines but if the strength of the current to be maintained constant in the mains, is to be of less value, say 6 or 8 amper-es, then the regulating brush 1d, should'be moved forward in the direction toward t-he dotted line position.

17 shows incandescent lamps connected to the mains 5 and 6 and 18 is a storage battery connected to said' mains. Switches may be employed to open the main circuit, between the battery and the dynamo, but such switches not being of presentinterest, 1 have made the circuits as simple as possible for the purpose of more clearly explaining my particular syst-em of regulation and its operation.

lln the field magnet frame of the dynamo electric machine it is assumed that-the windings 9 and 9, 10y and 10 surround the salient poles of the magne. The circuit through the field winding is fromV the point 11, through the coils 9 and 9 to the point 20, where the intermediate brush 14 is connected at the junction of the coils 9 and 10, this part of the circuit 1 have called circuit a. From the brush 14 to the point 1'2, through the coils 10 and 10 1 have called circuit b. 'llhe circuit through the coils 10 and 10 1 have called circuit c and the circuit between the mains 5 and 6 1 have called circuit e-ci.

The operation of my regulating dynamo is as follows: The dynamo, being directly connected to the engine, begins to' generate appreciable current when the armature thereof is rotated at the rat-e of about 600 R. l?. M. and the current rises rapidly until a speed of 1200 is attained when the current has ar` rived at its maximum value of 91j to 10 amperes. 1t is now desirable to maintain the current, in the main circuit, at a point not greater than 9% amperes at speeds varying from 1200 to 3000. When the current has reached its normal value at which it is to be maintained constant or 911,- amperes, at a speed of 1200 R. P. M., the current through the circuit a or the coils 9 and 9 lwill have decreased from 1-1- amperes to a little less than ampere, and the current flowing from the auxiliary regulating brush 14 through circuit b will have increased from 0 to 1?,- amperes. When the speed of the dynamo has reached 1500 revolutions the current passes through the coils 9 and 9 in a reverse direction from brush 14 to the brush 7 until the current flowing through this path reaches about three quarters amperes when the manetta dynamo is running 3000 1t. P. M. rlihis effect is produced, in my opinion, by the shifting of the commutating point, due to the reaction of the armature, as diagrammatically shown in Figs. 2 and 3.

1n F ig. 2 the full line 21 represents the distribution of the electromotiveforce around the commutator 15, when there is no distortion of the field flux by the reactive effect, produced by the armature, due to the tendency of increased current in the armature. 1n this condition it will be noted that there is very little difference of potential between the brushes 14 and l and that current will flow from brush 7 to brush 3 and from brush 14 to brush 8. 1f the ideal commutating points be circumferentially displaced from the points at which the brushes" bear upon the commutator, by distortion of the field due to the reaction of the armature upon the field magnets, as shown by dotted line in F ig. 3, it will then be observed that there is considerable fall of potential, in reverse direction, from brush 14 to brush 7 and that is accompanied by the reversal of the current through the coils 9 and 9 after the machine has 'reached a speed of 1500 1t. P. M.

Referring to Fig. 3; if the regulating brush 14 be set ahead, as shown in dotted lines in Fig. 1 this elfect will be increased so that a greater reverse current will flow through this circuit a and more greatly reduce the current flowing in the circuit e-a, or the main circuit, when the currentv will then be maintained, substantially constant, between 71j,- and 3 amperes.

l have given the best explanation, and theory of operation, that ,1 know, and whether or not my theory be correct, the fact remains that the actual operation of this device is substantially as shown, and throughout a range of speed of the armature from 1200 to 3000 R. P. M. and that the current remains substantially constant,with out the necessity of mechanically moving any part of the dynamo, for the purpose of accomplishing the automatic regulation.

lt am fully aware that a third intermediate or auxiliary brush has been used for purposes of regulation, as a means for maintaining constant potential in shunt wound dynamos, or constant .current in series wound dynamos, but in such prior devices the automatic movement of the auxiliary brush, over the surface of the commutator, was essential for accomplishing the regulation, but 1 am not aware that a shunt wound dynamo has heretofore been used wherein regulation was accomplished, in the manner described, without the necessity of moving the brush for maintaining a constant current in the mains, in such a manner, and wherein the value of the current to he maintained constant could he changed by the movement of the regulating brush to a greateror less distance from a given main brush, and then fixed.

While I have herein described in some detail a specific embodiment of my invention and havegiven my ideas regarding the theory of operation involved, I do not desire to be limited to or bound by any statement regarding such opinion 'further than defined bythe appended claims.

1. A constant current, self regulating dynamo-electric machine'h'aving an armature and two main brushes bearing' on the commutator thereof at commutating points for a practically, undistorted field, for connection to the mains `of a working circuit, and an 'auxiliary regulating brush fixed relatively current, in said main circuit, under varying.

speed of said armature.

2. A constant current, self regulating dynamo-electric machine havingl an armature and two main brushes bearing on the commutator thereof at commutatimg` points for a practically, undistorted field, vfor connection to the mains of a working circuit, a normally xed auxiliary, regulating brush capable of adjustment and to be fixed to bear on the commutator at any selected point between said main brushes, shunt windings for field magnets of said dynamo, havingr their terminals connected to Isaid main brushes and a connection between said auxiliary regulating Vbrush and an intermediate point in said field windings whereby the fixed location of said auxiliary brush will control the value of the current that will be constantly delivered in the mains.

In testimony whereofI hereunto set my hand in the presenceof two witnesses.

1 GORDON SAYRE.

In the presence ofa V. T. APPLE,

E. V. MARTIN. 

